On 05/31/2016 02:07 PM, Vlastimil Babka wrote:
On 05/31/2016 08:37 AM, Joonsoo Kim wrote:
@@ -3695,22 +3695,22 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
else
no_progress_loops++;
- if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
- did_some_progress > 0, no_progress_loops))
- goto retry;
-
+ should_retry = should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
+ did_some_progress > 0, no_progress_loops);
/*
* It doesn't make any sense to retry for the compaction if the order-0
* reclaim is not able to make any progress because the current
* implementation of the compaction depends on the sufficient amount
* of free memory (see __compaction_suitable)
*/
- if (did_some_progress > 0 &&
- should_compact_retry(ac, order, alloc_flags,
+ if (did_some_progress > 0)
+ should_retry |= should_compact_retry(ac, order, alloc_flags,
compact_result, &compact_priority,
- compaction_retries))
+ compaction_retries);
+ if (should_retry)
goto retry;
Hmm... it looks odd that we check should_compact_retry() when
did_some_progress > 0. If system is full of anonymous memory and we
don't have swap, we can't reclaim anything but we can compact.
Right, thanks.
Hmm on the other hand, should_compact_retry will assume (in
compaction_zonelist_suitable()) that reclaimable memory is actually
reclaimable. If there's nothing to tell us that it actually isn't, if we
drop the reclaim progress requirement. That's risking an infinite loop?
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